Comparative biokinetics of tritium in rats during continuous ingestion of tritiated water and tritium-labeled food

Takeda, Hiroshi; Lu, Honglin; Miyamoto, Kiriko; Fuma, Shoichi; Yanagisawa, K.; Ishii, Nobuyoshi; Kuroda, Nakabumi

doi:10.1080/09553000010017117

Cited by 10 publications

(8 citation statements)

References 12 publications

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“…Since 14 C ingested as food (e.g., wheat) would be incorporated into all kinds of organic components of the tissues, it should be reasonable to expect a high dose rate in tissues with high organic content, such as adipose tissue. We previously reported (Takeda et al 2001) experimental results of dose rate estimations from chronic exposure to 3 H-wheat, similar to the present study. As compared with the result, the dose rates to the majority of tissues from 14 C-wheat intake were higher by a factor of 3.1 to 5.5.…”

Section: Discussionsupporting

confidence: 92%

Biokinetics of Radiocarbon Ingested as a Food in Rats

Takeda¹,

Fuma²,

Miyamoto³

et al. 2009

Health Physics

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Biokinetics of radiocarbon (C) in rats during 14 wk of continuous ingestion of C-wheat was investigated to obtain the dosimetric data on organic C ingested as a food. After the start of continuous ingestion of C-wheat, the concentrations of C in both wet and dry tissues gradually increased and showed a tendency towards a steady-state condition for most of the tissues, except adipose tissue. The steady-state condition was observed at 10 wk in the majority of tissues, but was obtained at 3 wk in liver. The steady-state concentrations in wet tissues ranged from about 10% to 40%, and those in dry tissues ranged from about 80% to 100% of the concentration of C in the ingested food. The highest steady-state concentrations in both wet and dry tissues were observed in liver. When compared the concentrations among tissues at the end of 14 wk of continuous ingestion, adipose tissue was the highest in wet tissue and the lowest in dry tissue. From the concentrations of C in wet tissues at the 14th week, the radiation dose rates to individual tissues were estimated. The dose rates were different among the tissues. The highest dose rate was observed in adipose tissue. The next highest dose rates were found in liver and small intestine, while lower doses were measured in testis and lung. The differences in the dose rate among the tissues seemed to be mainly dependent on the variation in the organic content of each tissue.

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Section: Discussionsupporting

confidence: 92%

Biokinetics of Radiocarbon Ingested as a Food in Rats

Takeda¹,

Fuma²,

Miyamoto³

et al. 2009

Health Physics

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“…For dairy cows the parameter which resulted in the greatest variation in estimated transfer coefficients was milk yield. The range in estimated transfer coefficients demonstrates the potential errors associated with assuming single values of transfer coefficient for 3 Ff.…”

Section: Parameter Effectsmentioning

confidence: 99%

“…Equation (8) Experimentally following НТО intake, equilibrium specific activities of OBT in tissues (SA£J£*) in the range 0.2-0.3 of those of НТО in body water () [3] have been determined. Assuming that the specific activity of НТО in whole body water is equal to the specific activity of НТО in tissue water (i.e.…”

Section: Km Bmentioning

confidence: 99%

“…There are four pathways of 3 If we make the following assumptions: (i) dietary water absorption is complete; absorption of organically bound hydrogen (OBH) is described by the diet digestibility (FD); all OBH is lost via oxidation to HHO (direct excretion of body OBT is negligible being only a few percent of the total loss [2]); the loss of water from the body is described by a first order rate coefficient, ?и*=0.693/Тш where Tw is the body water turnover half-life. We can then write the rate of change of body hydrogen in the form of water (HHO kg H) and organically bound hydrogen (OBH kg H) as:…”

Section: Derivation Of Equilibrium Transfer Parametersmentioning

confidence: 99%

“…The wealth of knowledge concerning carbon and hydrogen metabolism can be utilised used with the available radioecological data to derive more applicable models. Here, we derive a steady state model for predicting 3 H transfer to animal products from an understanding of animal nutritional needs and body composition.…”

Section: Introductionmentioning

confidence: 99%

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The derivation of tritium transfer parameters for farm animals on the basis of a metabolic understanding

Galeriu¹,

Melintescu²,

Beresford

et al. 2002

Radioprotection

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Abstract. In contrast to many radionuclides (which often have no biological function) H has a stable analogue which is an elemental component of major nutrients, animal tissues and drinking water. Therefore concepts used to predict the transfer of other radionuclides are not valid for 3 H.In this paper we present an approach for the derivation of tritium transfer parameters which is based on the metabolism of hydrogen in animals. The derived transfer parameters separately account for transfer, to and from, free (i.e. water) and organically bound tritium. A novel aspect of the approach is that tritium transfer can be predicted to any animal product for which the required metabolic input parameters are available.Predicted equilibrium transfer coefficients are compared to available independent data. Agreement is good (R 2 =0.97) with the exception of the transfer from tritiated water to organically bound 3 H in ruminants. This may be attributable to characteristics of ruminant digestion.Tritium transfer coefficients will vary in response to the metabolic status of an animal and the use of a single transfer coefficient from diet to animal product is. inappropriate. However, we demonstrate that concentration ratios are less subject to metabolic variation and are a more useful parameter than transfer coefficients.

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A metabolic derivation of tritium transfer coefficients in animal products

Galeriu¹,

Crout

Melintescu³

et al. 2001

Radiation and Environmental Biophysics

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Tritium is a potentially important environmental contaminant originating from the nuclear industry, and its behaviour in the environment is controlled by that of hydrogen. Animal food products represent a potentially important source of tritium in the human diet and a number of transfer coefficient values for tritium transfer to a limited number of animal products are available. In this paper we present an approach for the derivation of tritium transfer coefficients which is based on the metabolism of hydrogen in animals. The derived transfer coefficients separately account for transfer to and from free (i.e. water) and organically bound tritium. A novel aspect of the approach is that tritium transfer can be predicted for any animal product for which the required metabolic input parameters are available. The predicted transfer coefficients are compared to available independent data. Agreement is good (R2=0.97) with the exception of the transfer coefficient for transfer from tritiated water to organically bound tritium in ruminants. This may be attributable to the particular characteristics of ruminant digestion. We show that tritium transfer coefficients will vary in response to the metabolic status of an animal (e.g. stage of lactation, diet digestibility etc.) and that the use of a single transfer coefficient from diet to animal product is inappropriate. It is possible to derive concentration ratio values from the estimated transfer coefficients which relate the concentration of tritiated water and organically bound tritium in an animal product to their respective concentrations in the animals diet. These concentration ratios are shown to be less subject to metabolic variation and may be more useful radioecological parameters than transfer coefficients. For tritiated water the concentration ratio shows little variation between animal products ranging from 0.59 to 0.82. In the case of organically bound tritium the concentration ratios vary between animal products from 0.15 (goat milk) to 0.67 (eggs).

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Comparative biokinetics of tritium in rats during continuous ingestion of tritiated water and tritium-labeled food

Abstract: Radiation dose rates estimated at the end of continuous ingestion showed that tritiated wheat gave higher dose rates than tritiated water by a factor of 1.3 to 4.5, but the factors were within 2.0 in the majority of tissues except for small intestine and adipose tissue.

Cited by 10 publications

References 12 publications

Biokinetics of Radiocarbon Ingested as a Food in Rats

Biokinetics of Radiocarbon Ingested as a Food in Rats

The derivation of tritium transfer parameters for farm animals on the basis of a metabolic understanding

A metabolic derivation of tritium transfer coefficients in animal products

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